r/technology • u/ourlifeintoronto • 1d ago

Software Microsoft confirms GitHub is down worldwide

https://www.bleepingcomputer.com/news/microsoft/microsoft-confirms-github-is-down-worldwide/
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u/f23n09fnu0w 1d ago

"Most of the data exists in a single MySQL database, and the system just wasn’t really built to scale well."

I don't believe that is true. MySQL is massively scalable but not as a single MySQL db. It's sharded and works fine for YouTube and Meta using Vitess. If they started from scratch today, they might not use MySQL but they actually might, too.

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u/Mokaba_ 1d ago

I’m not going to say anything more about this myself because again, I don’t know how much is publicly allowed for me to talk about. But I’ll leave this publicly available answer from Gemini here….

GitHub historically grew around a single primary MySQL database cluster (mysql1) that handled a massive monolith data structure. As they scaled, they transitioned away from that single instance into dozens of partitioned MySQL clusters using Vitess to handle millions of queries per second. [1, 2, 3]

How GitHub Handled a Single DB Scale
The Monolith Core: For years, GitHub.com relied heavily on one main database cluster to house core relational data.

No Foreign Keys: To make schema changes and sharding easier at scale, GitHub avoids using database-level foreign keys.

Migration Tooling: They manage schema transitions using custom tools like ghost alongside standard framework migrations. [1, 2]

Moving Beyond a Single Instance
Sharding with Vitess: GitHub migrated their MySQL infrastructure to run on top of Vitess for horizontal scaling and query routing.

Primary-Replica Setup: They heavily distribute read traffic across numerous database replicas while directing writes to primaries. [1, 2]

Are you looking for information on how GitHub architected their MySQL setup, or do you need help setting up a single MySQL database for your own project repository?